Robust Precision Positioning Control on Linear Ultrasonic Motor

TL;DR

This paper presents a systematic control approach for ultrasonic motors that employs piecewise affine models and model predictive control to improve precision by effectively compensating for friction effects.

Contribution

It introduces a novel systematic method using piecewise affine models combined with model predictive control for enhanced precision in ultrasonic motor positioning.

Findings

Improved tracking accuracy demonstrated in simulations.

Effective friction compensation using the proposed model.

Simplified gain scheduling scheme achieved.

Abstract

Ultrasonic motors used in high-precision mechatronics are characterized by strong frictional effects, which are among the main problems in precision motion control. The traditional methods apply model-based nonlinear feedforward to compensate the friction, thus requiring closed-loop stability and safety constraint considerations. Implementation of these methods requires complex designed experiments. This paper introduces a systematic approach using piecewise affine models to emulate the friction effect of the motor motion. The well-known model predictive control method is employed to deal with piecewise affine models. The increased complexity of the model offers a higher tracking precision on a simpler gain scheduling scheme.